As the debate hots up concerning the rightful destination of the BBC Sports Personality of the Year award – Lewis Hamilton's mantelpiece in Switzerland or Rebecca Adlington's in Derbyshire – cycling fans might reasonably wonder what Nicole Cooke has done, or more accurately hasn't done, to be a 125-1 no-hoper in the betting.

Maybe it is that her fellow Olympic gold medal-winners Chris Hoy and Bradley Wiggins have weakened the case for any one cyclist to be honoured. Or maybe it's that, for whatever reason, the 25-year-old Welshwoman has not been embraced to the collective bosom like the younger Adlington. Yet her achievements this year, insofar as one can compare apples with oranges, or saddles with Speedos, are even more remarkable. No Olympic road-racing champion had ever become world champion in the same year before Cooke, in one of the most thrilling races cycling has ever seen – and that includes men's races – triumphed in Varese, northern Italy, in September.

Significantly, though, she would probably not have won the world championship had she not already prevailed in Beijing. In Varese she manifestly rode with the confidence of an Olympic gold medallist, making her moves boldly but astutely, and striking with one final devastating overtaking manoeuvre just metres from the line after almost 140 kilometres of cat and mouse. Moreover, it was the fresh golden glow of the woman in the same colours that gave her team-mates Emma Pooley and Sharon Laws the confidence to support her. In cycling circles they hesitate to anoint Cooke as the greatest female cyclist these islands have ever produced – Beryl Burton was five-times world champion in an era before women's road-racing was an Olympic event – but her claim to sporting greatness is unarguable, and she began to stake it years ago.

I first met Cooke at her parents' house in Wick, a village near Bridgend, in July 2002. She was 19, and in her A levels the previous summer had scored straight As in geography, biology and maths. She could have had her choice of universities, but even her old schoolteachers accepted that she had been right to jettison her formal education, becoming instead a professional cyclist with the Deia-Pragma-Colnago team based in Italy.

We discussed her fierce ambition to win Olympic gold, as well as the titles she had already chalked up. For example, she had won four junior world titles, three of them in different disciplines in a single year, and I later asked a keen follower of professional cycling, which at the time I was not, to explain the breadth of that achievement. He told me that to win three junior world titles in a year, one of which was the mountain-biking championships in Vail, Colorado, even though she had not competed on a mountain bike for months and months, was "freaky, it's Forrest Gump stuff".

Well, that "freaky, Forrest Gump stuff" has now yielded the Olympic title she so craved, and also a measure of celebrity that this time brings me not to her mum and dad's place in Wick, but to a London photographic studio where she is being snapped to promote Nike's "Here I am" campaign to encourage more young women to take up sport. Afterwards she sits down with me and I am instantly reminded of the keenly intelligent and determined teenager I met six years ago, but with an added poise.

I ask her whether the ambition still burns as intensely as it did when I met her before. "Oh definitely, yeah," she says. "I'm still very motivated by sport, and next season [as world champion] I get to wear the rainbow

jersey for the whole year. The rainbow jersey is so iconic in cycling, it's incredible, so every time I ride a bike, even in practice, it will be fantastic. That's very motivating because there'll be no hiding in the bunch. I want to live up to my status. And of course I'm very focused now on London. I'm very excited about the next four years."

The 2012 Olympics to which she refers would be her fourth Games had the British Cycling Federation not denied her the chance to compete in Sydney eight years ago. She was told that, at 17, she was too young. And even now when I raise this, her naturally sunny countenance clouds over.

"I was the best rider in Britain at the time, I definitely deserved to go," she says, flatly. "It wasn't just that they made the decision, it was that they didn't have the right. It says in the Olympic charter that age should not be a barrier, in fact a local lawyer heard about the story and got in touch. He was all ready to take up my case. But there was too much bureaucracy involved."

At 17 that must have been hard to take? "Well, I deserved to go and that couldn't change. I couldn't do any more." But did it not sweeten the moment even more intensely when she finally prevailed in Beijing? "Yes, but I could have done without it, and to have had experience in Sydney would have really helped in Athens [where she finished a disappointing fifth]. I remember thinking after Athens that I'd put so much work into it and not even finished with a medal, and wondering whether I was prepared to do all that for another four years, and maybe still not win. I thought, 'Phew, am I ready for that?'"

As it turned out, she was, and for many of us who watched on television, Cooke winning in Beijing remains one of the most striking images of the sporting year. For one thing, it was the first of a marvellous haul of 19 gold medals for, as we had to learn to say, Team GB. But it is memorable mostly for Cooke's paroxysms of uninhibited joy as she crossed the line, and I ask her whether there was some pent-up emotion in her ecstasy.

"Well, I don't think Sydney came out, if that's what you mean. I'd moved on from that. But a lot of emotion, definitely. I was remembering that only months beforehand I'd had a knee injury and it was looking touch and go whether I'd even make the Olympics. It was more a reflection of that. And crossing the line's so strange, you know, because you're at your absolute physical limit and then it's all released. You lose all your power, tension and drive literally from one centimetre to the next. You go from concentration and determination to relief and joy."

It is eloquently expressed: women's cycling could do a lot worse than Cooke as a role model. And indeed there is tangible evidence that she has inspired people to get on their bikes in the months since Beijing, men as well as women.

"It's hard to judge numbers," she says, "but I know it's happening from the letters I've had, and people who've been in touch via my website. Just last Saturday in a restaurant a lady on another table came over to thank me, telling me that her son had just started road-racing because of watching me. That's fantastic, but there are so many good reasons to take up cycling. You can do it for pleasure, for commuting, for competition, and you get loads of benefit from it. Cycling just for fun is a good starting point. It's not like basketball or football where there's a winner and a loser. You can just go out for a ride and get a sense of freedom, and power, and discovery. And it's very social."

In Cooke's rather evangelical proponence of cycling there is perhaps a hint of why she has not captured hearts quite like Adlington has since Beijing. She seems almost disconcertingly in thrall to the bike, and when I ask her what she does away from the saddle, she says, eyes shining, that she has been working on a sort of guidebook to cycling. I press her for things that maybe have nothing to do with two wheels, and she seems startled by the question. "Oh, I enjoy my downtime. I watch DVDs, listen to music, do a bit of cooking..."

Of course, if she were not utterly wedded to her sport she would not be the champion she is, a champion like no female cyclist before her. "I realised in the days after the Olympics I had a chance to create history in the sport," she says, "and I knew I was good enough to win the world championships. I came up with a plan to keep a balance between the excitement of the Olympics, that feelgood factor that I wanted to harness, and basic everyday training. In a way I needed my body to be calm, but my mind to be super-excited."

She struck that balance perfectly, and by the time she enjoyed the rather belated Olympic victory parade in London, she could unequivocally call herself the best female road-racer on the planet. "But I knew going into the world championships that I had nothing left to prove. It wasn't like my whole season was based on one race. I didn't have to win." Which is in a sense doubtless why she won. But on a physiological rather than psychological level, it is also the case that even by the standards of road-racers she has a formidable "engine" (and, big admirer though I am of the 4-7 shot to win the BBC Sports Personality of the Year award, it is not one held together by nuts and bolts). I ask how she keeps it, as it were, oiled.

"Well, I've started working with a new coach over the last year, Fabio Bartolucci, and he has stressed the importance of recovery time, letting the body regenerate. I'm very careful in the afternoons after training, and I know I can develop by one or two per cent each season. I haven't plateaued yet." And she will still, I observe, be only 33 at the 2016 Olympics. "Yes, but racing into your thirties is for those who start later. Some people only come into cycling after university, and 15 years puts them at 35. I've already been going for 14 years. The late twenties is my time."

With Cooke already on top of the world, it is hard to see her being knocked from her pedestal if she continues to improve over the next four years. Not by fair means. But in cycling, foul means are always a possibility. Does she worry about drug use in the sport?

"Not particularly. All that concerns is me is what I do, so when I look in the mirror I'm happy with what I see. I'm not concerned with what other riders do." Not even if they beat her by cheating? "To be honest, no. I wouldn't feel bad about that because I wouldn't have lost against a better rider, would I? Besides, there are very few [drug cheats]compared to men's cycling, because the men have to be strong as juniors, then pass to an Under-23 team, and if they don't get through that they're not going to be a pro. At each stage they're being funnelled in, and they're desperate to make the next step. And the temptations are much greater. Women's cycling is more about the love of the sport, because there aren't the financial rewards. But even so, there are people who do cheat and I can't imagine how they feel." There is genuine puzzlement in the bright blue eyes of the world and Olympic champion. "It's a betrayal of themselves first of all," she says, softly.

Nicole Cooke is an ambassador for the Nike "Here I Am" Campaign helping to inspire young women to participate in sport. Nike has also launched an interactive website – www.nikehereiam.com – which offers young females the chance to connect with other girls across the UK and Europe to share their sports stories and passions.

Cooke-ing the books

3h 32m 24s

Cooke's time, over the 126km course at this year's Olympic road race, which secured Great Britain their first gold medal at the Beijing Olympics.

15 dragons

The number of Welsh rugby internationals, including Rob Howley and J P R Williams, who attended Cooke's school, Brynteg Comprehensive, in Bridgend.

8 years

The number of consecutive years Cooke has been crowned British women's road-race champion. She won the first of her nine titles as a 16-year-old back in 1999.

200 golds

Cooke's gold medal in the women's road race at this year's Beijing Olympics was gold number 200 for Great Britain since the modern Olympics began in 1896 (by the end of the Games that total had grown to 218).

21 years

Cooke's age when she became the youngest-ever winner of the prestigious Giro d'Italia Femminile – one of the Grand Tours of women's cycling.